As the flooring industry evolves, so does its terminology. The recent article in Floor Trends Magazine, “What’s in a Name: Self-Leveling Underlayment Terminology Clarified,” highlights a critical shift in how professionals refer to self-leveling materials. The American National Standards Institute (ANSI) now defines these products as Flowable Hydraulic Cement Underlayment (FHCU)—a more accurate term that reflects the reality that these materials do not level themselves but instead require proper installation and substrate preparation.
This redefinition places greater emphasis on the role of primers, which are essential for ensuring FHCU performance. Primers regulate absorption, promote adhesion, and help create a smooth, level surface—critical factors for the success of any flooring system. Among the most effective primers available today are those based on Acronal polymer dispersions, which offer tailored solutions for a range of subfloor conditions.
Acronal 4312 is widely regarded as the best overall performer. Its styrene acrylic chemistry provides a balanced combination of fast drying, excellent thin coat coverage, and reliable build. This makes it ideal for installers who need a versatile primer that performs consistently across different substrates and installation environments.
For thicker applications, Acronal 4624 is the standout choice. Formulated with all-acrylic monomers, it excels in high-build scenarios where surface irregularities need to be corrected before applying FHCU. While it ranks lower in drying speed and thin coat performance, its strength lies in its ability to create a robust, supportive base layer, especially important when working with uneven or porous subfloors.
Acronal 5041, a silinized styrene acrylic dispersion, offers the fastest drying time and serves dual roles as both a primer and surface sealer. It performs exceptionally well in thin coat applications and is particularly useful in fast-paced or moisture-sensitive environments. Its sealing capability adds an extra layer of protection, helping to stabilize the substrate and improve the bond between the FHCU and the flooring material.
All three Acronal products contribute to two key outcomes emphasized in the recently published article and help with two key features: creating a smooth surface and improving adhesion. A smooth, level subfloor not only enhances the appearance of the finished floor but also ensures that materials like tile, vinyl, or hardwood bond properly. This is especially important in today’s installations, where larger formats and thinner materials demand greater substrate flatness and stability.
As the industry continues to adopt the FHCU terminology and the standards behind it, choosing the right primer becomes more than a technical decision—it becomes a strategic one. Acronal technologies offer flooring professionals the performance, reliability, and flexibility needed to meet these evolving expectations and deliver installations that last.